Telescopes and Lenses????????

[event horizon]

I have three different eyepieces, on one it says: H25mm, on another it says: SR4mm, and on the third one it says: H12.5mm, Which one of these is the strongest???...

AND, I also have a lens that says,"3X Barlow" on it, what is this for???

[Carlos_dfc]

Hi

To calculate magnifiction, you divide the telescope's focal length, by the size of the eyepiece being used - which means that lower number eyepieces, will give higher magnifications.
Take a look on your telescope, it should have the focal length written on it somewhere, or if not, it should be in the manual.

A few examples
telescope focal length 1400, eyepiece 25
1400 / 25 = 56x magnification
telescope 1000, eyepiece 12.5
1000 / 12.5 = 80x magnification
and so on.....
(If you want to post the focal length of your scope, I can give you the right figures for your setup)


A 'barlow' is a magnification booster.
You put the barlow in first, then put the eyepiece into the barlow.
If yours is marked 3x, then it multiplies the magnification by 3 times.
So, using one of the examples above...
If you add the barlow into the 1400/25=56x setup
You would get 56 x 3 = 168x magnification